Killer kids may get flexible sentences

Young killers could have their jail terms cut when more is known about their rehabilitation prospects, under legislation proposed for NSW.

The provisional sentencing scheme, to be introduced into state parliament, will apply to convicted murderers who commit their crimes between the ages of 10 and 16.

Attorney-General Greg Smith SC said the new law would allow judges to set a provisional sentence, which could be revised down after more is known about the killer's development.

"Judges have spoken about the difficulty of sentencing young killers when no definite diagnosis or prognosis is available," Mr Smith said in a statement on Friday.

"This way they won't need a crystal ball, but they can make sure they get it right."

He said the proposal was prompted by a report from the Sentencing Council that endorsed the introduction of provisional sentences.

"Experts often say they cannot assess a young person's future prospects because their brains are still developing," Mr Smith said.

Under provisional sentencing, a judge could order that a child receive treatment and be properly monitored in jail.

Juvenile Justice would report to the court on the offender's progress, and the judge would need to set the final sentence within five years of the provisional sentencing and at least a year before the provisional non-parole period expires.